on February 2th, 1912, the patent No.117955 was awarded to the patent owner George A. Carney by the U.S. Patent Office, which was an invention about improving the handcuff locking device. It was this invention that introduced the swinging arch ratchet into the handcuff, which made the handcuff go out of the heavy, clumsy and inconvenient history and opened a chapter of modern handcuff. In fact, most of the plate handcuffs still in use at present are improved on the basis of this invention. Later, George A. Carney transferred this patent to James Milton Gill, who started the Peerless handcuff company in Springfield, Massachusetts, USA, and has been producing handcuffs, fetters, waist chains, keys and other restraints since 1914.